lpcware

USB0 built-in DMA controller burst size can't be changed

Discussion created by lpcware Employee on Jun 15, 2016
Latest reply on Jun 15, 2016 by lpcware
Content originally posted in LPCWare by Pavel Boldin on Fri Jul 11 11:54:52 MST 2014
Hello everyone,

There is a register 'BURSTSIZE' among the controlling registers of the USB0 Host controller. Its purpose according to the user manual UM10503 is to change burst sizes of the DMA master bursts.

However, I'm unable to change this register value neither through the JTAG nor directly from the CPU:
> mdw 0x40006160          
0x40006160: 00001010
> mww 0x40006160 0x101
> mdw 0x40006160     
0x40006160: 00001010

Here 'mdw' means 'memory dump word' and 'mww' means 'memory write word'. (These are OpenOCD commands)

Resetting the controller is not helping either:
> mww 0x40006140 0x2
> mdw 0x40006140   
0x40006140: 00080000
> mdw 0x40006160     
0x40006160: 00001010
> mww 0x40006160 0x101
> mdw 0x40006160     
0x40006160: 00001010

(Commands are the same)

What can be a problem here?

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